Why Do I Get Hives When I Sweat

Our health is greatly influenced by physical exercise. However, engaging in physical activity or the resultant sweat itself may be a cause of skin disease.¹

The term "Cholinergic" describes a region of the neurological system that regulates heart rate dropping, blood vessel dilatation, and muscular contraction.²

Urticaria is the term used in medicine for hives or rash. Hives are a skin response that abruptly produces lumps, elevated areas, or both, on the skin. The lumps and elevated areas might appear bloated and are frequently itchy.³

This article examines cholinergic urticaria's causes, signs, and triggers as well as possible therapies. Learn about the treatment options, such as lifestyle changes and medication, that can help people manage cholinergic urticaria and lessen the impact it has on their everyday lives. Learn more about this particular form of urticaria and how to manage it well for a higher standard of living.

What is cholinergic urticaria?

Cholinergic urticaria (CholU) is a kind of rash that is brought on by an increase in body temperature following physical activity, sweating, eating spicy food, stress, or passive heating^.4 

The rashes present as a number of itchy, tiny, 1 to 5 mm spots or scar that remains for a short while (up to an hour) ⁵ and often start on the neck and trunk before spreading to the face and limbs.⁸

The rash, which is often referred to as heat hives, can develop anywhere on the body and is typically quite itchy. Exercise, nervousness, and taking hot baths or showers are a few examples of behaviors that might trigger cholinergic urticaria. 

Cholinergic Urticaria is also known as  cholinergic angioedema, hives, or heat rash.⁶Prevalence is higher in young adults particularly those who are between the ages of 23 and 28^.5   Although the condition can begin later in life, it often affects women.⁷

Causes of hives when sweating

The patients' sweats contain histamine and other unidentified compounds that make them hypersensitive, and they react by breaking out in wheals as the material leaks from the syringeal ducts into the dermis—possibly due to duct occlusion.

Causes of cholinergic Urticaria

Any action that makes you sweat a lot might induce cholinergic urticaria.

Examples comprise:

• Exercise
• Hot baths
• Hot tubs
• Saunas
• Warm rooms, andexposure to hot environments such as the sun
• Ever, anger, or stress, and eating spicy food
• Alcohol consumption

Symptoms of cholinergic urticaria

• Elevated skin lesions
• The lesions frequently come in groups
• They frequently itch
• They might be flesh tone, pink, or red
• It's possible for the colors to fade if you press in the centre
• These bumps often disappear after 24 hours, although new ones may develop
• They might be as little as a pinprick or as large as several inches

Not all hives manifest as bumps. Lesions might also include:

• Small blotches,
• Thin, elevated lines, and 
• Patches

The reason determines how long it takes for the lesions to develop.⁹

^{Any combination of the following characteristics might describe the rash:}

• Itching or tingling at the beginning of the rash
• Burning or itching in the regions where the rash is present
• Small wheals or raised lumps on the skin
• Bigger wheals that cause more noticeable areas of swelling, and 
• Angioedema, or swelling of the deeper layers of the skin

Diagnosis

The patient's medical history and a provocation test that is adequate for their age and overall health are used for the diagnosis.

Prior to now, the diagnosis has been confirmed using both strenuous activity and passive warming that can raise the core body temperature. 

When a wheal-flare reaction emerges immediately or within a short period of time following vigorous activity or passive warming and often goes away within 15 to 60 minutes, Cholinergic urticaria is suspected. 

In both clinical and research contexts, the intradermal injection of 100 g of methacholine in 0.1 ml of saline solution is  utilized as an additional test for the diagnosis of Cholinergic urticaria.

A positive reaction is indicated by a wheal-flare reaction that takes place within one minute of the injection.⁴

Possible complications

In rare cases, heat bumps may be linked to a systemic reaction like:

Hypotension

• Bronchospasm
• Angioedema
• Headaches
• Shortness of breath and wheezing
• Diarrhea and cramping in the abdomen
• There have also been reports of hepatocellular damage, asthma, anaphylactoid responses, and anaphylactic reactions¹⁰

Treatment 

Options for management and treatment differ depending on the person.

They consist of:

• Drugs such as the antihistamine cetirizine (Zyrtec)
• The antihistamine and asthma drug ketotifen (Zaditor)
• The anabolic steroid danazol (Danocrine), and
• Sometimes the anti-IgE monoclonal antibody omalizumab (Xolair)

Prevention

• Lifestyle changes to avoid triggers like avoiding warm environments and activities
• Avoiding spicy foods
• Reducing alcohol intake
• Avoid ultraviolet (UV) phototherapy
• Stress management strategies, if stress appears to be a contributing factor²

Summary

Due to the production of histamine and other molecules when perspiring, cholinergic urticaria can result in hives. Additionally, urticaria brought on by exercise, heat, and aquagenic urticaria can cause hives to break out when perspiring. Although hives normally go away in a few hours, it is still advisable to see a doctor for a precise diagnosis and tailored treatment. Keeping away from triggers like heat and strenuous activity may help reduce hives' sweating symptoms.